1. Field of the Invention
The present invention relates to an image information processor such as a facsimile, copy machine and the like and method for using the same. More specifically, the present invention relates to a paper sheet conveying apparatus for an image information processor, which is controlled to prevent a paper sheet with image information recorded thereon from a skew carriage.
2. Description of the Related Art
For example, in image information processors, such as facsimiles, copy machines, printers and the like, there is a paper sheet conveying apparatus for conveying a paper sheet (with image information recorded thereon) to an image reading part. This paper sheet conveying apparatus has the function of correcting a skew advancement of the paper sheet by arranging a leading end of the paper sheet.
The paper sheet conveying apparatus that has the function of correcting a skew advancement of the paper sheet is disclosed in U.S. Pat. No. 5,749,570 and is schematically illustrated in FIG. 1.
Referring to FIG. 1, a conventional paper sheet conveying apparatus of an image information processor includes a paper sheet separating roller 11 and a paper sheet guide 12 installed above and below respectively, for separating one paper sheet from a plurality of stacked paper sheets and conveying it to an image reading part 5, and a white roller 21 installed opposite to the image reading part 5, for reading the image information on the paper sheet.
As shown in FIG. 1, the image reading part 5, which is upwardly biased by a spring to closely contact the white roller 21, reads the image information of the paper sheet by an image reading sensor (not illustrated) into analogue signals, converts the analogue signals into digital signals, and outputs the digital signals.
A reference numeral 6 indicates a paper presence sensor for sensing the presence or absence of the paper in a paper stack pad 4. A reference numeral 7 indicates a paper leading edge sensor for sensing the leading edge of the advancing paper sheet and outputting the sensed information.
The paper leading edge sensor 7 outputs one set of control signals for matching the image reading starting point to the image reading starting time for the image reading part 5, and another set of control signals for shifting the revolutions of a driving motor from the forward direction to the reverse direction or vice versa, thus for correlatively driving the paper sheet separating roller 11 and the white roller 21.
As shown in detail in U.S. Pat. No. 5,749,570, the paper sheet conveying apparatus as described above arranges the leading edge of the paper and corrects the skew advancement by shifting the revolution direction of the driving motor and by using a mechanical timer mechanism.
Accordingly, the conventional paper sheet conveying apparatus of the image information processor is very complicated in its constitution, and has to be improved in its precision. Also, since the white roller 21 is momentarily stopped and driven by the mentioned system to correct the skew carriage of the paper, a precision control is not guaranteed, particularly when high speed feeding is carried out.
Further, in the conventional paper sheet conveying apparatus, a separate paper-ejecting roller cannot be easily installed in view of its constitution. That is, in the case where a paper ejecting roller is installed, the paper ejecting roller revolves in the reverse direction during the reverse revolution of the driving motor, and therefore, the paper sheet moves in the reverse direction, with the result that the ejection of the paper sheet becomes impossible.
Accordingly, in the conventional paper sheet conveying apparatus, the paper-ejecting roller is excluded, and therefore, high-speed paper ejection becomes impossible, with the result that the image information processing is limited in its speed and capacity.
The present invention is intended to overcome the above-described disadvantages of the conventional technique.
An aspect of the present invention is to provide a paper sheet conveying apparatus of an image information processor and method, in which the correction precision for the skew advancement of the paper sheet is improved.
Another aspect of the present invention is to provide a paper sheet conveying apparatus of an image information processor, in which the conveying-driving units are driven interactively and selectively by a single driving source, thereby improving the paper sheet ejection efficiency suitably for a large capacity paper sheet conveying apparatus.
In achieving the above aspects, the paper sheet conveying apparatus of an image information processor according to the present invention includes a driving unit which interactively and selectively drives a paper sheet separating roller, a paper sheet aligning roller and a paper sheet ejecting roller at different conveying stages, the paper sheet separating roller, the paper sheet aligning roller and the paper sheet ejecting roller are sequentially disposed for uni-directionally conveying an image-recorded paper sheet.
Further, the driving unit includes a driving motor which is mode-shiftably driven in a forward mode direction and a reverse mode direction, a power cleaving mechanism for selecting a rotational driving force in a certain direction to transmit the driving force through different paths in accordance with the driving modes, a first power transmitting system which drives the paper sheet separating roller and the paper sheet ejecting roller correspondingly with a conveying direction by being selectively connected to the power cleaving mechanism; and a second power transmitting system which drives the paper sheet separating roller, the paper sheet aligning roller and the paper sheet ejecting roller in the conveying direction by being selectively connected to the power cleaving mechanism.
The power cleaving mechanism includes a main gear connected to an output shaft of the driving motor, and first and second cam gears respectively installed on both ends of the output shaft of the main gear to be moved in a linear direction, for advancing and withdrawing mutually along an axis of the main gear in accordance with the forward and reverse mode directions of the driving motor.
The first power transmitting system includes a first connection gear which is selectively connected in accordance with the straight movements of the first cam gear, and a first passive gear installed on a shaft of the paper sheet separating roller and a second passive gear installed on a shaft of the paper sheet ejecting roller so that the first and second passive gears are connected to the first connection gear.
The second power transmitting system includes a second connection gear which is selectively connected to the second cam gear, a connecting gear installed on a shaft of the paper sheet aligning roller, for being connected to the second connection gear, and a power transmitting means for selectively connecting the passive gear of the paper sheet ejecting roller.
The invention further provides for a paper sheet conveying apparatus of an image information processor, comprising means for interactively and selectively driving a paper sheet separating roller, a paper sheet aligning roller and a paper sheet ejecting roller at different conveying stages, the paper sheet separating roller, the paper sheet aligning roller and the paper sheet ejecting roller being sequentially disposed for uni-directionally conveying a paper sheet having a recorded image. The means for interactively and selectively driving includes a driving motor for being mode-shiftably driven in forward and reverse mode directions; and a power cleaving means for selecting a direction of a rotational driving force to transmit the driving force through different paths in accordance with driving modes. The means for interactively and selectively driving further includes means for driving the paper sheet separating roller and the paper sheet ejecting roller correspondingly with a conveying direction by being selectively connected to the power cleaving means when the driving motor is driven in one of the forward and reverse mode directions. Also included is a means for driving the paper sheet separating roller, the paper sheet aligning roller and the paper sheet ejecting roller in the conveying direction by being selectively connected to the power cleaving means when the driving motor is driven in another of the one of the forward and reverse mode directions.
The invention even further provides for a method for conveying a paper sheet in an image information processor, the image information processor having a paper sheet separating roller, a paper sheet aligning roller and a paper sheet ejecting roller. The method comprises feeding a paper sheet toward the aligning roller; and providing, selectively, a rotational driving force by a driving motor in a forward revolution to the paper sheet separating roller and to the paper sheet ejecting roller, wherein the paper sheet aligning roller is not provided with the rotational driving force and is not rotating. The method further includes conveying the paper sheet into the non-rotating aligning roller and a non-rotating back-up roller, which faces the aligning roller, for a predetermined amount of time; and shifting the driving motor to a reverse revolution so as to provide a rotational driving force, after the predetermined time has expired, to the paper sheet separating roller, the paper sheet aligning roller and the paper sheet ejecting roller, so that the paper sheet is conveyed to an image reading portion.